Ventilation device

ABSTRACT

A ventilation device ( 1 ) is proposed, in particular designed to ventilate a circuit board ( 2 ), preferably in or for a computer, wherein the ventilation device ( 1 ) is designed to produce a first cooling air stream ( 5 ) from a first fan ( 12 ) and to produce a second cooling air stream ( 7 ) from a second fan ( 13 ), wherein the first cooling air stream ( 5 ) and the second cooling air stream ( 7 ) flow through on different sides of an air stream boundary plane (L), preferably parallel to the air stream boundary plane (L), through a common ventilation plane (BL) perpendicular to the air stream boundary plane (L), wherein the directions of flow from the first fan ( 12 ) and the second fan ( 13 ) are crosswise to the air stream boundary plane (L), wherein the ventilation device ( 1 ) preferably is designed to be mountable such that the air stream boundary plane (L) coincides with a central plane of the circuit board.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent Applicaiton Ser. No.15/111,558, which is the United States National Stage under 35 U.S.C. §371 of PCT International Application No. PCT/EP2015/000202, filed onFeb. 2, 2015 and claiming priority to German Patent Application No. 102014 001 423.1, filed on Feb. 3, 2014.

This application is the United States National Stage under 35 U.S.C. §371 of PCT International Patent Application No. PCT/EP2015/000202, filedon Feb. 2, 2015, and claiming priority to German Patent Application No.10 2014 001 423.1, filed on Feb. 3, 2014.

BACKGROUND OF THE INVENTION Field of the Invention

The invention concerns a ventilation device. In particular, theinvention concerns a ventilation device for ventilating a circuit board,preferably in a computer.

Background of the Related Art

Various arrangements for ventilating a circuit board or the componentsof a circuit board are known. Examples of such arrangements according tothe prior art are shown in FIGS. 8A and 8B. FIG. 8A shows a circuitboard 100 with a component 101. The component 101 in this example is acentral processing unit (CPU). It is known to cool the component 101using an installed fan 102 that pulls a stream of air 103 from above andblows it directly downward onto the component 101. After flowing overthe component 101, the stream of air 103 is deflected by the circuitboard 100 and passes over the circuit board 100. FIG. 8B shows anothercircuit board 100 with components 101 on both sides of it. A fan 102 isplaced to the side of the circuit board and directs a stream of air 103onto one side edge of the circuit board 100, where the stream of air issplit and flows along the top and bottom sides of the circuit board 100to cool the components 101.

The available space inside a computer housing can be limited. It iscommon, in particular, to have multiple cards inserted into connectorstrips (“slots”), sometimes with predetermined small distances betweenthem. However, ventilation devices of the type described have acomparatively large height in relation to the thickness of the installedcircuit board or are added above the components installed on the circuitboard, which often makes the use of these types of ventilationproblematic. For example, in the applicant's series X3/X5 OSBiz wallsystems, especially when using a UC booster card, due to the greatercomponent thickness and installation on both sides and in connectionwith a temperature-sensitive hard drive, forced ventilation in thehousing is desirable, because the natural convection inside the housingis stretched to its limits. Changing the housing, the motherboard, orthe installation positions is difficult to do. Especially critical hereis the hard drive, which may have a temperature limit that should not beexceeded, such as 55° C., that varies depending on the manufacturer.

BRIEF SUMMARY OF THE INVENTION

One goal of the present invention is to offer a circuit boardventilation device that at least partially eliminates the disadvantagesof the prior art. A specific goal of the invention is to offer a circuitboard ventilation device that allows two-sided ventilation of a circuitboard with the smallest possible device height.

Embodiments are based on the concept of placing two fans next to acircuit board, as an extension of the circuit board's plane, wherein thefan axes are at an angle, in particular perpendicular, to the circuitboard's plane, and wherein the air currents from the fan flow over thecircuit board's plane and are directed by appropriate air guide elementssuch that a stream of air flows largely tangentially over each side ofthe circuit board.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 a representation of a ventilation device according to a firstembodiment of the present invention in a first configuration;

FIG. 2 a representation of the ventilation device according to the firstembodiment in a second configuration;

FIGS. 3A to 3F several enlarged views and sections of the ventilationdevice according to the first embodiment in the first operating mode;

FIG. 4 a three-dimensional representation of the ventilation deviceaccording to the first embodiment in the second operating mode;

FIG. 5 a representation of the back of a ventilation device from thefirst embodiment;

FIG. 6 a representation of the ventilation device according to a secondembodiment of the present invention in the second operating mode;

FIG. 7 a representation of the ventilation device according to a thirdembodiment of the present invention in the second operating mode;

FIGS. 8A and 8B Side views of ventilation devices according to the priorart.

The figures are schematic illustrations and not necessarily according toscale. The graphic representations and their descriptions are intendedto illustrate the principle of the invention and shall in no wayrestrict the invention.

DETAILED DESCRIPTION OF THE INVENTION

As discussed above in the Brief Summary of the Invention, embodimentsare based on the concept of placing two fans next to a circuit board, asan extension of the circuit board's plane, wherein the fan axes are atan angle, in particular perpendicular, to the circuit board's plane, andwherein the air currents from the fan flow over the circuit board'splane and are directed by appropriate air guide elements such that astream of air flows largely tangentially over each side of the circuitboard.

In this regard, one aspect of the invention proposes a ventilationdevice designed to produce a first cooling air stream from a first fanand to produce a second cooling air stream from a second fan, whereinthe first cooling air stream and the second cooling air stream flowthrough on different sides of an air stream boundary plane, preferablyparallel to the air stream boundary plane, through a common ventilationplane perpendicular to the air stream boundary plane, wherein thedirections of flow from the first fan and the second fan are crosswiseto the air stream boundary plane. The ventilation device is intended inparticular for ventilating a circuit board, preferably in or for acomputer, and is designed preferably to be installed in such a way thatthe air stream boundary plane coincides with a central plane of thecircuit board.

A ventilation plane for purposes of the invention is a plane facing anobject to be ventilated and through which the cooling air streams travelin order to ventilate the object. An air stream boundary plane forpurposes of the invention is a plane that can be established as aboundary between the two cooling air flows at any time after they leavethe ventilation device. This means that each component immediatelyadjacent to the ventilation device and located in the air streamboundary plane has a tangential flow of cooling air streams over it onone side of the air stream boundary plane.

It should be understood that the cooling air streams can be mixed at acertain distance from the ventilation device, if the separation of thecooling air streams is not maintained by an object located in the airstream boundary plane. Crosswise to the air stream boundary plane forpurposes of the invention means not parallel, so at an angle or,preferably, perpendicular or essentially perpendicular to the air streamboundary plane. In other words, the first and second cooling air streamsare deflected by the ventilation device from the crosswise direction to90°±x (depending on the angular placement of the fan), so that they flowparallel or essentially parallel to each other along the air streamboundary plane that coincides with a circuit board plane, for example,when the invention is used.

Because fans generally have a flat design, i.e., are thinner in the flowdirection than across it, the diagonal or in particular 90°—angledarrangement with its subsequent flow deflection makes it possible forthe fan to be installed flat with respect to the ventilation direction.This can also reduce the unit height. Two sides of an object, inparticular a circuit board, can be ventilated purposefully, and the airstreams are directed so that the first cooling air stream flows along afirst circuit board flat side of the circuit board and the secondcooling air stream flows along a second circuit board flat side of thecircuit board. Air, for purposes of the invention, is any cooling gasmix, in particular ambient air. A circuit board for purposes of theinvention is, in general, a flat unit with two flat sides (circuit boardflat sides or populated sides) and generally four edge sides.Conceivably, circuit boards can also have one (e.g., round, oval, orsimilar), two (e.g., spear-shaped), three, or five or more edge sides.Both circuit board flat sides can be populated, and the invention canalso be used if only one side is populated but heat is also conducted tothe other side. It is also possible for a heat-generating component tobe installed on one portion of the circuit board and generate heat toboth surface sides. The ventilation plane can coincide with the circuitboard.

According to one preferred embodiment of the ventilation device, thefirst cooling air stream and the second cooling air stream are dischargestreams or suction streams from the first fan or the second fan. Inother words, the air streams travel in the same preferred directionthrough the ventilation plane. A suction stream is an air stream drawntoward a fan, and a discharge stream is an air stream pushed away from afan. Because the first and second cooling air streams flow inessentially the same direction with respect to a main flow directionparallel to the air stream boundary plane, a relatively large volume ofair can also be forced along the length of the object to be ventilated,whereby an at least essentially uniform temperature profile can also beachieved on the front and back sides of the object. The main flowdirection is understood to be an axis that runs perpendicular to theventilation plane within the air stream boundary plane. The cooling airstreams can have lateral angular deviations from the main flow directionand also extend in a fan shape.

According to one alternative preferred embodiment of the ventilationdevice, the first cooling air stream is a discharge stream from thefirst fan or from the second fan, and the second cooling air stream is asuction stream from the other of the first and second fans. In otherwords, the air streams travel in opposite preferred directions throughthe ventilation plane. This means that the first and second cooling airstreams flow at least essentially in opposite directions with respect toa main flow direction parallel to the air stream boundary plane. Thisresults in a push-pull arrangement. Thus, for example, if the airstreams cannot escape at the downstream side of the ventilated object,it is possible to achieve an air flow around the object such that thefirst cooling air stream (discharge stream) flowing along a first sideof the object is deflected at the end and flows along the second side ofthe object as a second cooling air stream drawn through the second fan(suction stream).

According to one preferred embodiment, the ventilation device has ahousing with a ventilation side that defines a or the ventilation planeand on which the housing is at least partially open, and a mountingplate that splits the ventilation side and defines a or the air streamboundary plane, wherein the mounting plate has at least two fans or isconfigured to accept at least two fans of such a type that a cooling airstream from each fan is or can be directed through a respective openingin the mounting plate, wherein each fan has an assigned air guidancechamber that is open toward the ventilation side and is closed oressentially closed on all other sides except for the respective openingin the mounting plate. The problem addressed by the present invention issolved by this device for the same reasons as the ones stated above forthe aforementioned ventilation device. An air guidance chamber for thepurposes of the invention is understood to be a chamber that is part ofthe housing and deflects air streams forced by the fans such that theirflow paths run through the ventilation plane. This allows the air streamflows according to the invention to be advantageously generated.

According to one preferred embodiment of the ventilation device, thefans are placed on different sides of the mounting plate. In otherwords, the ventilation device or the mounting plate is configured insuch a way that the fans are or can be placed on different sides of themounting plate, or are or can be placed essentially on different sidesof the mounting plate. Preferably, the fans are placed on the sides ofthe mounting plate opposite from the respective air guidance chamber, sothat they do not impede the air flow in the air guidance chamber.However, it is also possible and included in the invention for one ormore fans to project partially through the opening in the separationplate, which can further reduce the installed height of the ventilationdevice.

According to another preferred embodiment of the ventilation device,each air guidance chamber for one of the fans is separated on its sideof the mounting plate from the area of another one of the fans, whereineach of them in particular has a separation wall that extends preferablyperpendicular to the mounting plate and especially preferably at anangle to the ventilation side. In other words, one of the air guidancechambers for one of the fans is installed on one side of the mountingplate, for example using suitable crosspieces, cover plates, etc., andis separated from the area of the respective other fan by the separationwall. In this configuration, angular placement of the separation wallsis chosen in particular, so that the air guidance chambers widen towardthe ventilation side of the ventilation device. This makes it possibleto achieve a fan-shaped stream flow of the cooling air stream thatspreads out parallel to the air stream boundary plane. If the fans areplaced next to each other relative to the narrow side of the circuitboard, then the total width of the circuit board can at leastessentially be covered by the cooling air stream. In one variation ofthe invention, if the fans are not placed next to each other but ratherone in front of the other, which can be desirable with very narrowcircuit boards, with a suitably shaped separation wall the adjacentchamber of the fan nearer to the ventilation side can be housed insidethe air guidance chamber of the farther fan, so that the adjacentchamber of the fan nearer to the ventilation side is enveloped by thecooling air flow from the farther fan. In this way, the separation wallscan be used to achieve effective separation and also suitable guidanceof the air streams.

According to one preferred embodiment of the ventilation device, themounting plate is a section of a circuit board, in particular thecircuit board to be ventilated. In other words, the circuit board has anarea in which the openings for the fans are placed, the fans are or canbe installed directly on the circuit board, and a housing or housingsections that create the chambers for deflecting the air stream are orcan be placed on the circuit board. In addition, fewer components areneeded with this embodiment, and the circuit board can be preconfiguredfor ventilation. The housing, or portions or halves of it, and fans canbe provided as an assembly. Assembly is easier and more secure, and itis no longer necessary to align the ventilation device with the circuitboard.

Preferred embodiments of the ventilation device are characterized inthat the housing contains or is made from or is essentially made from atleast one of the following materials:

-   -   plastic, in particular ABS (acrylonitrile-butadiene styrene), PC        (polycarbonate), or a mix thereof,    -   circuit board material,    -   metal, in particular aluminum or steel plate,    -   cardboard, paper, pasteboard, or similar.

According to one preferred embodiment of the ventilation device, asymmetrical connection port is provided for the electric power supply tothe fans, wherein the connection port preferably has a suitable negativepole for grounding and respective positive poles for supplying power toeach of the fans arranged symmetrically around the negative pole.Symmetrical in this context should be understood specifically to meanelectrically symmetrical. This allows for increased installation safetyby preventing voltage reversal.

Connection and voltage reversal safety can be improved even more in apreferred embodiment of the ventilation device, if the symmetricalconnection port has a form characteristic that unmistakably establishesa connection point. Such a form characteristic can include, withoutlimitation, a bevel, groove, or spline, a pin or recess, a tab, etc. Theform characteristic can also be a different distance between thepositive poles and the negative pole or an angled placement of thepoles. A plug belonging to a connection lead can then have thecorresponding complementary form characteristic.

The objective of the invention is also achieved by means of a method forventilating in particular a circuit board, preferably in or for acomputer, with the following steps: Generate a first cooling air streamfrom a first fan and a second cooling air stream from a second fan,wherein the first cooling air stream and the second cooling air streamflow through on different sides of an air stream boundary plane,preferably parallel to the air stream boundary plane, through a commonventilation plane perpendicular to the air stream boundary plane, thedirections of flow from the first fan and the second fan are crosswiseto the air stream boundary plane, and ventilation is established in sucha way that the air stream boundary plane coincides with a center planeof the circuit board. The problem addressed by the present invention issolved by this method for the same reasons as the ones stated above forthe aforementioned ventilation device.

Additional features, tasks, advantages and details of the presentinvention will become more apparent from the following description ofconcrete exemplary embodiments and their representation in drawings inthe included figures. It is understood that features, tasks, advantagesand details of individual exemplary embodiments are transferable toother exemplary embodiments and are considered to be disclosed also inconnection with the other exemplary embodiments unless this is obviouslyinapplicable for technical or physical reasons. Exemplary embodimentscan be combined with other exemplary embodiments and that combinationcan also be considered an exemplary embodiment of the invention.

The invention is described below in more detail based on preferredexemplary embodiments and with reference to the figures.

A basic function process of a ventilation device 1 according to a firstbasic embodiment is explained here according to FIGS. 1 and 2. FIGS. 1and 2 are side views of the ventilation device 1, which is placed inappropriate operating position next to a circuit board 2. Air streamsare represented in the figure with bold arrows or, if covered bycomponents, with broken lines.

According to the representations in FIGS. 1 and 2, the circuit board 2is populated with components 3 on a top side 2 a and a bottom side 2 band has a center plane or circuit board plane L that runs through themiddle between the top side 2 a and the bottom side 2 b of the circuitboard 2. The ventilation device 1 has a ventilation side 1 a facing thecircuit board 2. The ventilation side 1 a defines a ventilation plane BLthat is perpendicular to the circuit board plane L and through whichpass cooling air streams used by the ventilation device 1 to cool orventilate the circuit board 2. The ventilation device 1 has two fanslocated inside of the ventilation device 1 (not visible here). Theventilation device 1 can be operated in two basic configurations whichwill now be explained in detail.

FIG. 1 shows a first configuration of the ventilation device 1. In it, afresh air stream 4 is drawn through an opening (not shown here) in theunderside of the ventilation device 1, deflected inside of theventilation device 1 by appropriate air guidance elements, and pushedout above the circuit board plane L as a first cooling air stream 5through an opening (not shown here) in the ventilation side 1 a of theventilation device 1 in such a way that it leaves the ventilation device1 by passing through the ventilation plane BL, parallel to the circuitboard plane L on the top side 2 a of the circuit board 2. Similarly, asecond fresh air stream 6 is drawn through an opening (not shown here)in the top side of the ventilation device 1, deflected inside of theventilation device 1 by appropriate air guidance elements, and pushedout under the circuit board plane L as a second cooling air stream 7 toventilate the underside 2 b of the circuit board 2 through an opening(not shown here) in the ventilation side 1 a of the ventilation device 1in such a way that it leaves the ventilation device 1 by passing throughthe ventilation plane BL, parallel to the circuit board plane L on theunderside 2 b of the circuit board 2. The circuit board plane L can thusalso be called the air stream boundary plane L, which establishes aboundary between the first cooling air stream 5 and the second coolingair stream 7. After flowing over the circuit board 2, the first coolingair stream 5 and the second cooling air stream 7 combine into an exhauststream 8, which can leave a computer housing (not shown here) throughventilation slots (not shown here), for example. It should be noted thatthe air stream boundary plane L can then also be established by theoriginally separated cooling air streams 5, 7, if the circuit board 2 isnot available; in that case, of course, the cooling air streams 5, 7would then combine sooner. The first operating mode can also be calledpush ventilation (ventilation blown outward). The direction of the freshair streams 4, 6 is preferably selected such that a thermal updraft inthe enclosed space (such as a computer housing) is supported orutilized.

In one variation of the first operating mode, the two fans can work inthe opposite direction, so that air streams from the top side 2 a andunderside 2 b of the circuit board 2 are drawn through the ventilationplane BL and discharged onto the top and bottom sides of the ventilationdevice 1 as exhaust streams. This operating mode variation can also becalled pull ventilation (ventilation drawn in). It can be understood byreversing all air stream arrow directions in FIG. 1.

FIG. 2 shows a second operating mode of the ventilation device 1. Hereit is assumed that behind the circuit board 2, i.e. on one of the narrowsides of the circuit board 2 opposite the ventilation device 1, there isa housing wall 9 of a computer or another impediment that would hinderthe free flow of an exhaust stream. In the second operating mode, afirst fan operates as in the first operating mode in push mode, i.e., afresh air stream 4 is drawn in through the opening in the underside ofthe ventilation device 1, deflected, and discharged above the circuitboard plane L as a first cooling air stream 5 parallel to the top side 2a of the circuit board 2. Unlike the first operating mode, in the secondoperating mode a second fan operates in pull mode, i.e., a secondcooling air stream 7 that flows along the underside 2 b of the circuitboard 2 is drawn through the ventilation plane BL into the ventilationdevice 1, deflected there, and discharged through the opening in the topside of the ventilation device 1 as the exhaust stream 8. The secondcooling air stream 7, which ventilates the underside 2 b of the circuitboard 2, originates at least in part from the first cooling air stream 5that is reversed at the wall 9 into a reverse stream 10. The second airstream 7 is drawn in and reversed by the same fan and the same airguidance elements that draw in and reverse the second fresh air stream 6in the first operating mode (FIG. 1), except that the fans used hereoperate in the other direction. The reversal of the first cooling airstream 5 to become the reverse stream 10 is accomplished by the suctionaction of the fan operating in pull mode. The second operating mode canalso be called push-pull ventilation. It should be understood that inthis operating mode the working directions of the fans can also bereversed, so that all flow directions are reversed.

In both operating modes, the first and second cooling air streams 5, 7are generated by respective fans in the ventilation device 1. Ifappropriate, the fans can be different sizes, and it can in particularbe useful for a fan that works against the thermal updraft in thesurrounding space to be more powerful. In all cases, the air stream flowshould be such that the intermixing of fresh air and exhaust air isprevented or essentially prevented.

An interior arrangement of the ventilation device 1 will now bedescribed in greater detail based on FIGS. 3A to 3F. In this regard,FIG. 3A shows a top view in a plane and a direction indicated in FIG. 1by a dot-dash line and an arrow IIIA, FIG. 3B shows a cutaway view fromabove in a plane and a direction indicated in FIG. 1 by a dot-dash lineand an arrow IIIB, i.e., above the air stream boundary plane L, FIG. 3Cshows a cutaway view from above in a plane and a direction indicated inFIG. 1 by a dot-dash line and an arrow IIIC, i.e., under the air streamboundary plane L, FIG. 3D shows a cross-section view from the directionof the circuit board 2 in a plane and a direction indicated in FIG. 1and FIG. 3B by a dot-dash line and an arrow IIID, FIG. 3E shows acutaway view from the side in a plane and a direction indicated in FIG.3D by a dot-dash line and an arrow IIIE, and FIG. 3F shows a cutawayview from the side in a plane and a direction indicated in FIG. 3D by adot-dash line and an arrow IIIF. The ventilation device 1 is shown inall FIGS. 3A-3F in the first configuration according to FIG. 1.

FIG. 3A shows the ventilation device 1 from above with a section of thecircuit board 2. As shown in FIG. 3A, the first cooling air stream 5leaves the ventilation device 1 on the ventilation side 1 a in afan-shaped flow such that the cooling air stream 5 fans out from theright side toward the middle. The cooling air stream flowing under thecircuit board 2 (7, FIG. 1) is not shown in FIG. 3A, but it flows as canclearly be seen in other figures, also fan-shaped with an opposingfan-out direction. The ventilation side 1 a is designated hereinafter asthe front, and the opposite side as the back.

As can best be seen in FIG. 3D, which shows a cross-sectionapproximately in the middle and parallel to the ventilation plane (FIG.1), the ventilation device 1 has a housing 11, a first fan 12, and asecond fan 13. The housing 11 has a mounting plate 14, which forms theair stream boundary plane (L, FIG. 1), and a first opening 14 a and asecond opening 14 b. The first fan 12 is secured with screws 15 to anunderside of the mounting plate 14 in the area of the first opening 14a, and the second fan 13 is secured with screws 15 to a top side of themounting plate 14 in the area of the second opening 14 b. On the topside of the mounting plate 14 there is a first crosspiece 16 extendingperpendicularly, which is partially covered on top by a first coverplate 17 that runs parallel to the mounting plate 14. Similarly, on theunderside of the mounting plate 14 there is a second crosspiece 18extending perpendicularly, which is partially covered on the bottom by asecond cover plate 19 that runs parallel to the mounting plate 14.

The course of the first crosspiece 16 is best seen in FIG. 3B, whichshows the ventilation device 1 in a horizontal section above the circuitboard 2 (the air stream boundary plane L, FIG. 1). The first crosspiece16 has a separation wall 16 a that runs diagonally between the openings14 a, 14 b over the cover plate 14 and thereby separates an area aroundthe first opening 14 a from an area around the second opening 14 b abovethe cover plate 14. Hereinafter the area of the first opening 14 a isalso designated as the area of the first fan 12 and the area of thesecond opening 14 b is also designated as the area of the second fan 13,wherein the areas around the fans 12, 13 are understood to extend in aperpendicular direction to the mounting plate 14 and to be bordered bythe crosspieces 16, 18. In the area of the first fan 12 (the firstopening 14 a) a side wall 16 c adjoins the separation wall 16 a at aback edge of the cover plate 14, running along a back wall 16 b and thenbending toward the front at right angles as it continues. In the area ofthe second fan 13 (the second opening 14 b) another side wall 16 eadjoins the separation wall 16 a at the front edge (ventilation side 1a, see FIG. 3A) of the cover plate 14, running along a front wall 16 dand then bending toward the back at right angles as it continues. Inother words, the first crosspiece 16 runs in an angled S-shape such thatthe area of the first fan 12 (the first opening 14 a) is open toward theventilation side 1 a and the area of the second fan 13 (the secondopening 14 b) is closed toward the ventilation side 1 a. Given thediagonal placement of the first separation wall 16 a, the area of thefirst fan 12 expands toward the front edge (ventilation side 1 a, seeFIG. 3A). As shown in FIGS. 3A, 3D, 3E, and 3F, the first cover plate 17is provided only in the area of the first fan 12, i.e., only on thefirst separation wall 16 a, the back wall 16 b, and the subsequent sidewall 16 c, while the area of the second fan 13, i.e., the area of thefront wall 16 d and the subsequent other side wall 16 e, is open towardthe top.

The course of the second crosspiece 18 can best be seen in FIG. 3C,which shows the ventilation device 1 in a horizontal cross-section underthe circuit board 2 (the air stream boundary plane L, FIG. 1). Thesecond crosspiece 18 has a separation wall 18 a that runs diagonallybetween the openings 14 b, 14 a over the cover plate 14 and therebyseparates an area around the second fan 13 from an area around the firstfan 12 above the cover plate 14. In the area of the second fan 13 (thesecond opening 14 b) a side wall 18 c adjoins the separation wall 18 aat a back edge of the cover plate 14, running along a back wall 18 b andthen bending toward the front at right angles as it continues. In thearea of the first fan 12 (the first opening 14 a) another side wall 18 eadjoins the separation wall 18 a at the front edge (ventilation side 1a, see FIG. 3A) of the cover plate 14, running along a front wall 18 dand then bending toward the back at right angles as it continues. Inother words, the second crosspiece 18 runs in an angled S-shape thatcorresponds to the S-shape of the first crosspiece 16 mirrored in theplane IIID in FIG. 3B such that the area of the second fan 13 (thesecond opening 14 b) is open toward the ventilation side 1 a and thearea of the first fan 12 (the first opening 14 a) is closed toward theventilation side 1 a. Given the diagonal placement of the secondseparation wall 18 a, the area of the second fan 13 expands toward thefront edge (ventilation side 1 a, see FIG. 3A). As shown in FIGS. 1, 3D,3E, and 3F, the second cover plate 19 is provided only in the area ofthe second fan 13, i.e., only on the second separation wall 18 a, theback wall 18 b, and the subsequent side wall 18 c, while the area of thefirst fan 12, i.e., the area of the front wall 18 d and the subsequentother side wall 18 e, is open toward the top.

As can best be seen in FIG. 3D, the fans 12, 13 are both located on theside of the mounting plate 14 that is open toward the top and thereforenot closed off by a cover plate 17 or 19, while the areas closed off bythe cover plates 17 or 19 are free of components. These empty areas canbe used as flow deflection areas, which are open toward the ventilationside 1 a of the ventilation device 1 (see FIGS. 3E, 3F). For purposes ofthe invention, these flow deflection areas are designated as airguidance chambers, while the areas around the fans 12, 13 are designatedas sub-chambers. Therefore, the area open toward the bottom in which thefirst fan 12 is located defines a first sub-chamber 20, the area opentoward the top in which the second fan 13 is located defines a secondsub-chamber 21, a first air guidance chamber 22 is formed by themounting plate 14, the first crosspiece 16 (first separation wall 16 a,back wall 16 b, side wall 16 c), and the first cover plate 17, and asecond air guidance chamber 23 is formed by the mounting plate 14, thesecond crosspiece 18 (second separation wall 18 a, back wall 18 b, sidewall 18 c), and the second cover plate 19.

Because the separation walls 16 a, 18 a intersect diagonally, as viewedfrom above, the fan-shaped flows of the cooling air streams 5, 7 alsointersect as viewed from above. It should be understood that thecrosspieces 16, 18 can be one piece or can be made of multiple piecesjoined together. As can be seen in FIGS. 3A, 3B, 3D, the mounting plate14 extends laterally beyond the side walls of the crosspiece 16, 18,which makes it easier to mount the ventilation device. Of course, it isalso possible for the mounting plate 14 to be located in other places,for example on the front or back sides, or to use other means ofmounting the device.

FIG. 4 shows a three-dimensional representation of this embodiment ofthe ventilation device 1 with a portion of the circuit board 2. Thisrepresentation shows the pathways of the air streams 4, 5, 7, 8 in thesecond operating mode according to FIG. 2.

FIG. 5 shows a representation of the back of a ventilation device fromthe first embodiment. As seen in FIG. 5, there is a three-polesymmetrical connection port 24 with a central common ground connector 24a for both fans 12, 13, a first positive pole 24 b for supplying powerto the first fan 12, and a second positive pole 24 c for supplying powerto the second fan 13. A first fan connection port 12 a for the first fan12 has a negative pole connected to the common ground connector 24 a anda positive pole connected to the first positive pole 24 b of thesymmetrical connection port 24. A second fan connection port 13 a forthe second fan 13 has a negative pole connected to the common groundconnector 24 a and a positive pole connected to the second positive pole24 c of the symmetrical connection port 24. A common positive pole canalso be provided instead of a common ground connector 24 a. The commonconnector 24 a can be located between the other two connectors 24 b, 24c to create an axis- and/or point-symmetrical connection port 24 or anaxis- and/or point-symmetrical connecting element, which because of itssymmetry can be located on a card/circuit board with reverse-polarityprotection. Because the connection port 24 is symmetrical, a connectormaking (external) contact with the connection port can be plugged intoor onto the connection port 24 with reverse-polarity protection.However, a symmetrical power supply is not absolutely necessary. Inanother embodiment, the power supply as configured as a parallelconnection. The fan connections to the power supply can be three-pole(3-pole). In another embodiment of the invention, in addition to thepower supply there is also a tach signal for controlling the rpm rate orspeed of the fan(s) and thereby the air volume moved by the fan(s) perunit of time on a control unit for the fan(s). By evaluating the tachsignal, the rotation speed of the fan(s) can be monitored and adjusted.In addition, it is possible to determine and assess whether there hasbeen a fan failure.

The connection port 24 has a shape characteristic 24 d in the form of abevel on one corner. Because only a matching connector with thecorresponding complementary shape characteristic fits into theconnection port 24, this ensures reverse-polarity protection of thepower supply for the fans 12, 13 with a single connector.

Because the crosspieces 16, 18 (FIGS. 3B, 3C) have no back walls in thearea of the sub-chambers 20, 21, the fan connection ports 12 a, 13 a areeasily accessible from the back of the ventilation device 1. To theextent necessary for reasons of stability, the crosspieces can also beextended farther into the area of the sub-chambers 20, 21. If thesub-chambers 20, 21 are completely closed off at the back, the fanconnection ports 12 a, 13 a could still be accessed from above or below.

FIG. 6 shows a three-dimensional representation of the ventilationdevice 1 according to a second embodiment of the present invention inthe second operating mode. This embodiment is a variation of thepreviously described first embodiment. Except where stated otherwisebelow, the explanations, assemblies, effects, and advantages of thefirst embodiment and its variations apply equally or similarly to thisembodiment.

As shown in FIG. 6, the cover plates 17, 19 extend over the entiresurface of the crosspieces 16, 18. However, in the area of thesub-chambers 20, 21 (where the fans are to be located), the side walls16 e, 18 a (FIGS. 3B, 3C) of the crosspieces 16, 18 are omitted and theback walls run all the way to the sides, so also through the areas ofthe sub-chambers 20, 21. In other words, only the sides of thesub-chambers 20, 21 are open to the outside. Fresh air and/or exhauststreams (depending on the operating mode, here fresh air stream 4 andexhaust stream 9) flow in or out through the open sides of thesub-chambers 20, 21 of the ventilation device 1.

This arrangement is useful in cases where free air streams are possibleor ventilation slots are available only from or on the side of theventilation device 1. In this case it is advantageous to insert the fanspartially into the openings 14 a, 14 b, so that bottlenecking in thesub-chambers 20, 21 is prevented.

FIG. 7 shows a three-dimensional representation of the ventilationdevice according to a third embodiment of the present invention in thesecond operating mode. This embodiment is a variation of the firstembodiment. Except where stated otherwise below, the explanations,assemblies, effects, and advantages of the first embodiment and itsvariations and modifications apply equally or similarly to thisembodiment.

As shown in FIG. 7, the fans 12, 13 are located on the mounting plate 14one behind the other rather than next to each other with respect to thecircuit board 2, so that here the second fan 13 is assumed to be closerto the circuit board 2 (ventilation side 1 a) than the first fan 12. Thefirst sub-chamber 20 is therefore square-shaped and located in the lowerrear area, and the first air guidance chamber 22, also square-shaped,extends over the entire length of the ventilation device 1. The firstcrosspiece 16 consists of multiple parts and has a first part thatencloses the first air guidance chamber 22 on the side and back, and asecond closed circular part located inside the first air guidancechamber 22, creating the second sub-chamber 21 as an inset within thefirst air guidance chamber 22, so that the first cooling air stream 5flows around it from the side. Here the circular shape of the secondpart of the first crosspiece 16 that forms the second sub-chamber 21 isstreamlined to be more symmetrically drop-like in shape. The second airguidance chamber 23, which is again square-shaped, ends before the areaof the first fan, so before the first sub-chamber 20.

This arrangement is useful in cases where a circuit board 2 needs to beventilated from a narrow side. The fans can have varying power levels ordifferent flow resistances as needed.

The invention has been described based on preferred embodiments,variations, alternatives, and modifications and illustrated in thefigures. These descriptions and representations are purely schematic anddo not limit the protective scope of the claims, but rather are intendedonly as illustrative examples. It should be understood that theinvention, in the scope and to the extent described in the patentclaims, can be executed and modified in many ways without leaving theprotective scope of the patent claims.

For example, the invented ventilation device 1 can also be configuredsuch that there are radial fans inside the air guidance chamber, withinternal axial-radial or radial-axial flow deflection, whose radial in-or outflow is split or combined appropriately by the air guidancechambers, so that the axial in- or outflow passes through the openings14 a, 14 b.

The features of the invention described in relation to the illustratedembodiments, e.g., the common connection port 24 a according to FIG. 5,can also be part of other embodiments of the invention, e.g., in theventilation arrangement according to FIG. 6 and/or FIG. 7, except whenstated otherwise or when impossible for technical reasons.

LIST OF REFERENCE SIGNS AND SYMBOLS

1 Ventilation device

1 a Ventilation side

2 Circuit board

2 a First circuit board flat side (top side)

2 b Second circuit board flat side (bottom side)

3 Component(s)

4 Fresh air stream

5 First cooling air stream

6 Fresh air stream

7 Second cooling air stream

8 Exhaust stream

9 Wall

10 Deflected flow

11 Housing

12 First fan

12 a Fan connection port

13 Second fan

13 a Fan connection port

14 Mounting plate

14 a First opening

14 b Second opening

15 Screws

16 First crosspiece

16 a First separation wall

16 b Back wall

16 c Side wall

16 d Front wall

16 e Side wall

17 First cover plate

18 Second crosspiece

18 a Second separation wall

18 b Back wall

18 c Side wall

18 d Front wall

18 e Side wall

19 Second cover plate

20 First sub-chamber

21 Second sub-chamber

22 First air guidance chamber

23 Second air guidance chamber

24 Symmetrical connection port

24 a Ground connector

24 b First positive pole

24 c Second positive pole

24 d Form characteristic

100 Circuit board (prior art)

101 Component

102 Fan unit

103 Air stream

BL Ventilation plane

L Air stream boundary plane/Circuit board plane

The above list is an integral part of the description.

What is claimed is:
 1. A ventilation device, comprising: a first fanconfigured to produce a first cooling air stream having a firstdirection of flow; a second fan configured to produce a second coolingair stream having a second direction of flow, the second direction offlow being opposite the first direction of flow, wherein the firstcooling air stream flows along a first side of a circuit board and thesecond cooling air stream flows on a second side of the circuit boardthat is opposite the first side of the circuit board; a housing, thehousing having a mounting plate positionable adjacent the circuit board,the first fan attached to a first side of the mounting plate within afirst air guidance chamber at least partially defined by a plurality ofwalls connected to the mounting plate and the second fan attached to asecond side of the mounting plate within a second air guidance chamberat least partially defined by a plurality of walls connected to themounting plate, the second air guidance chamber being separated from thefirst air guidance chamber so that that first cooling air stream flowsaround a sub-chamber of the second air guidance chamber in which thesecond fan is positioned as the first cooling air stream flows towardthe circuit board in the first direction of flow; wherein one of thewalls that at least partially defines the first air guidance chamber isa separation wall that extends perpendicular to the mounting plate andat an angle to a ventilation side and one of the walls that at leastpartially defines the second air guidance chamber is a separation wallthat extends perpendicular to the mounting plate and at an angle to theventilation side; and wherein the mounting plate is a segment of thecircuit board.
 2. The ventilation device of claim 1, wherein the firstcooling air stream is a suction stream and the second cooling air streamis a discharge stream.
 3. The ventilation device of claim 1, wherein thefirst cooling air stream is a discharge stream from the first fan andthe second cooling air stream is a suction stream.
 4. The ventilationdevice of claim 1, wherein the first side of the mounting plate is a topside and the second side of the mounting plate is an underside of themounting plate.
 5. The ventilation device of claim 1, wherein thehousing contains a material selected from the group consisting ofplastic, circuit board material, aluminum, steel, cardboard, paper andpasteboard.
 6. The ventilation device of claim 1, further comprising asymmetrical connection port configured to accommodate an electric powersupply to the first fan and the second fan, wherein the connection porthas a common negative pole for grounding and respective positive polesfor supplying power to each of the first fan and the second fan arrangedsymmetrically around the negative pole.
 7. A method for ventilating acircuit board comprising: providing a housing, the housing having amounting plate positionable adjacent the circuit board, a first fanattached to a first side of the mounting plate within a first airguidance chamber at least partially defined by a plurality of wallsconnected to the mounting plate and a second fan attached to a secondside of the mounting plate within a second air guidance chamber at leastpartially defined by a plurality of walls connected to the mountingplate, the second air guidance chamber being separated from the firstair guidance chamber, wherein the first side of the mounting plate is atop side of the mounting plate and the second side of the mounting plateis an underside of the mounting plate, and wherein one of the walls thatat least partially defines the first air guidance chamber is aseparation wall that extends perpendicular to the mounting plate and atan angle to the ventilation side and one of the walls that at leastpartially defines the second air guidance chamber is a separation wallthat extends perpendicular to the mounting plate and at an angle to theventilation side; producing a first cooling air stream having a firstdirection of flow via the first fan so that that a first cooling airstream passes around a sub-chamber of the second air guidance chamber inwhich the second fan is positioned as the first cooling air stream flowstoward the circuit board in the first direction of flow; and producing asecond cooling air stream having a second direction of flow that isopposite the first direction of flow, wherein the first cooling airstream flows along a first side of the circuit board and the secondcooling air stream flows on a second side of the circuit board that isopposite the first side of the circuit board wherein the mounting plateis a segment of the circuit board.
 8. The method of claim 7, wherein thefirst cooling air stream is a suction stream and the second cooling airstream is a discharge stream.
 9. The method of claim 7, wherein thefirst cooling air stream is a discharge stream from the first fan andthe second cooling air stream is a suction stream from the second fan.10. The method of claim 7, wherein the first air guidance chamber isopen toward a ventilation side and the second air guidance chamber isopen toward the ventilation side.
 11. The method of claim 7, wherein thehousing contains a material selected from the group consisting ofplastic, circuit board material, aluminum, steel, cardboard, paper andpasteboard.
 12. The method of claim 7, comprising: providing an electricpower supply to the first fan and the second fan via a symmetricalconnection port, the connection port having a common negative pole forgrounding and respective positive poles for supplying power to each ofthe first fan and the second fan arranged symmetrically around thenegative pole.
 13. A ventilation device designed to ventilate a circuitboard, comprising: a first fan configured to produce a first cooling airstream having a first direction of flow; and a second fan configured toproduce a second cooling air stream having a second direction of flow,the second direction of flow being opposite the first direction of flow,wherein the first cooling air stream flows along a first side of thecircuit board and the second cooling air stream flows on a second sideof the circuit board that is opposite the first side of the circuitboard; a housing, the housing having a mounting plate positionableadjacent the circuit board, the first fan attached to a first side ofthe mounting plate within a first air guidance chamber at leastpartially defined by a plurality of walls connected to the mountingplate and the second fan attached to a second side of the mounting platewithin a second air guidance chamber at least partially defined by aplurality of walls connected to the mounting plate, the second airguidance chamber being separated from the first air guidance chamber sothat that first cooling air stream flows around a sub-chamber of thesecond air guidance chamber in which the second fan is positioned as thefirst cooling air stream flows toward the circuit board in the firstdirection of flow; wherein the housing has a ventilation side thatdefines a ventilation plane, wherein the housing is at least partiallyopen on its ventilation side; wherein the first cooling air stream isdirectable through a first opening in the mounting plate and the secondcooling air stream is directable through a second opening in themounting plate; and wherein the first air guidance chamber is opentoward the ventilation side and the second air guidance chamber is opentoward the ventilation side.
 14. The ventilation device of claim 13,wherein the mounting plate is a segment of a circuit board.
 15. Theventilation device of claim 13, wherein the first cooling air stream isa suction stream and the second cooling air stream is a dischargestream.
 16. The ventilation device of claim 13, wherein the firstcooling air stream is a discharge stream from the first fan and thesecond cooling air stream is a suction stream.
 17. The ventilationdevice of claim 13, wherein the first side of the mounting plate is atop side and the second side of the mounting plate is an underside ofthe mounting plate.
 18. The ventilation device of claim 13, furthercomprising a symmetrical connection port configured to accommodate anelectric power supply to the first fan and the second fan, wherein theconnection port has a common negative pole for grounding and respectivepositive poles for supplying power to each of the first fan and thesecond fan arranged symmetrically around the negative pole.
 19. Theventilation device of claim 13, wherein the housing includes a material,the material including one or more of: plastic, circuit board material,metal, aluminum, steel, cardboard, paper and pasteboard.